Because the relay is composed of two parts: the coil and the contact group

Component symbol

Because the relay is composed of two parts of the coil and the contact group, the relay in the circuit diagram of the graphic symbols also includes the following two parts: a rectangular frame of the coil; a set of contact symbols to indicate the contact combination. When the contact is not more than the circuit is relatively simple, the contact group is often drawn directly on the side of the box on the line, this painting is called the centralized representation.

Electrical symbols and contact forms:

Relay coil in the circuit with a rectangular box symbol, if the relay has two coils, draw two parallel rectangular frame. At the same time, in the rectangular box or rectangular frame next to the relay of the text symbol "J". Relay contacts have two ways: one is to draw them directly on the side of a rectangular box, this expression is more intuitive. The other one is in accordance with the needs of circuit, the control circuit of individual contacts to their contacts, usually in the same relay and the coil side are the same symbols on the label, and the contact group number to show distinction. Relay manufacturers